Reishi: An Ancient Medicinal Mushroom

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You can find reishi tea, as well as many other reishi products, in your local health food store.
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Reishi mushrooms can be grown on logs or stumps, like they do in the wild.
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Where reishi mushrooms grow, and on what, is dependent on the region and species of reishi.
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Manufacturers keep up with the demands of the reishi industry by cultivating the mushrooms in large grow rooms.
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Depending on the desired shape for your reishi mushrooms, you can open or close their bags to regulate CO2 emissions.

My boots press into an emerald moss carpet as I scan an old-growth log for shiny, red, fan-shaped shelf mushrooms — the reishi. Medicinal reishis grow all over the world: from Europe to Asia, from South America to this quiet Pacific Northwest conifer grove. Anyone on a hike in late summer has likely seen them without realizing that these are the mushrooms believed by ancient Chinese emperors to grant immortality. I wish that, like the emperors, I could summon a court sorcerer to help me find them.

In 219 B.C., Emperor Qin Shihuangdi sent his sorcerer, Xu Fu, east from Xi’an on a quest for the “mushroom of immortality.” It was never found, and some said it was a sign that the emperor had lost the mandate of heaven. In ancient China, reishis symbolized health, good fortune, longevity, and even divinity. Emperors bore ruyi, royal scepters crowned with the curling, fan-shaped fungus. Medical practitioners served elixirs in dainty ceramic cups painted with reishis, and they ascribed to the fungi an unbelievable range of health benefits. In Traditional Chinese Medicine (TCM), reishis are believed to boost qi (life force) and they’re prescribed for both mind- and body-oriented health issues.

“When dried in the shade, powdered, and taken by the inch-square spoonful, they produce genie-hood,” recorded Daoist alchemist Ge Hong in his third-century text, Baopuzi. Of course today’s superfood industry doesn’t make quite such bold claims.

Mushroom Medical Research

Although they have not (yet) proven to be an elixir of immortality, medicinal reishis are still a big business. In a news release from Zion Market Research, it was estimated the global mushroom market, including reishis, was valued at $35.08 billion in 2015, and that number is expected to climb in the coming years. A quick search at my local health-food store uncovered reishi-filled capsules, powders, teas, extracts, and chocolate elixirs. Few companies dare to make specific health claims regarding this fungi, and those that do add plenty of asterisks. As of writing this, the Food and Drug Administration (FDA) has not approved any mushrooms for use as medicine. So for now, despite ongoing research, my reishi-infused hot chocolate may not really imbue me with anything more genie-like than relaxation.

However, in another 10 years, it might be advertised as “anti-cancer cocoa.” Although still not substantial enough to state any direct or official claims, much reishi research in the last decade has focused on the mushroom’s potential ability to slow or even halt tumor growth. Several in vitro studies, including a 2017 study by the National Cancer Institute in Naples, Italy, have found bioactive compounds in reishis to be effective growth inhibitors against a range of cancer cells including prostate, colorectal, breast, cervical, lung, and melanoma.

Of these compounds, possibly the best-researched are polysaccharides, which interact with our immune receptors. Reishis have an abundance of water-soluble β-D-glucans, which some studies have shown are absorbed by our bodies through the digestive tract before entering the lymphatic system. This is coincidentally a pathway of qi, and here they appear to activate macrophages, T-cells, and other tumor-killing parts of the immune system.

Polysaccharides, as well as ganoderic acids exclusively found in reishis, are also believed to help aid in suppressing tumors by interacting with cell DNA and possibly activating apoptosis, cutting short a cancer cell’s unnatural longevity and permitting it to die a proper cell death.

Reishis are also classified as adaptogens — substances that rebalance the body’s various systems. Because of this, reishis have the uncanny ability to either fan the flames of run-down or underperforming immune systems or to cool overactive ones, which is a benefit because overactive immune systems can cause allergic reactions and inflammation. The ganoderic acids in reishis seem to soothe asthma and infections and act as a blood thinner. Reishis are also recommended for insomnia to provide a more sound sleep. (See “All About Adaptogens” for more information on using reishis for sleep and immunity.)

Though many praise the minimal side effects of reishi compared to other Chinese herbs, as with any unapproved medicine still being researched on the market, take precaution when deciding to use it for medicinal purposes. It’s not recommended that reishi becomes a substitute for any other medication or health treatment. Avoid taking with blood thinners and medications that lower blood pressure.

Cultivating Reishi Mushrooms

A large swath of reishi studies come from China or Japan, where, by the 1970s, quests to find the mushroom were no longer necessary as people developed new technologies to grow them. Today, “divine mushrooms” are cultivated in massive indoor grow rooms. In my experience — unless a reishi product label specifies USA-grown — dried reishi slices, teas, or powders are often sourced from China. However, while most reishi retailers there label their mushrooms Ganoderma lucidum, it’s hard to know with 100 percent certainty which species they’re actually growing.

The mislabeling began in Western Europe, where G. lucidum is native, one 2012 study explains. This name was also introduced to China in the 1900s as scientific records catalogued different species of reishis, and the name G. lucidum stuck. However, when morphologically and molecularly compared to the true European G. lucidum, the Chinese species are not the same, rather akin to G. sichuanense.The study concludes: “The name G. lucidum as used for the Chinese species is erroneous and should be corrected.” That’s a tricky order.

China has around 70 reishi species, of which a portion have been used medicinally. The most ancient text to categorize them is attributed to the demigod emperor Shen Nong, who described six groups based on color and prescription, such as green for liver, yellow for spleen, or red for heart. Red is what we typically call G. lucidum, but there are at least 12 — and potentially more — other red reishi species so similar that researchers have despairingly lumped them together into a lucidum complex.

North America has a handful of species as well, so when researching what I should look for I called the next best person to a Qin court sorcerer: mycologist Drew Henderson, author of Fungal Freedom: A Guide to Wild Mushrooms of Washington State. He sells reishis and other mushrooms at the Olympia Farmers Market, supports ethical wildcrafting, and thinks the best way to experience the benefits of reishi is to cultivate them locally.

Plus, he continues, young reishis are delicious. His favorite way to eat them is as a tofu-replacement in soup; additionally, “if you gave it to someone fried in little pieces, they’d think it was delicious.” He describes them as “marshmallowy,” with a sweet and bitter flavor like chocolate or coffee. “Reishis are soft. Pithy is the word. [When harvesting reishis], you can just grab the base of it, twist, and it will pop right off and be squishy in your hand. With the other types of shelf mushroom, if you took a bread knife and tried to slice it you’d probably break your knife.”

To find them, Henderson says, look for the reishi’s preferred type of tree in late August or early September. “China’s G. lucidum likes sweeter, deciduous woods: plum, maple, or oak,” he says. Henderson adds that our local G. oregonense prefers Douglas fir, while G. tsugae, though more common on the East Coast can still be found in the Pacific Northwest, loves Western hemlock.

I wonder if old sorcerer Xu Fu knew which trees to search for. At any rate, I’m sure Emperor Qin Shihuangdi would have been better off drinking the tea of any species of reishi than the elixir that eventually killed him, which was made of mercury.

How to Grow Reishi

Don’t feel like going on a quest for your medicinal elixir? Reishi is one of the easiest mushrooms to cultivate on your kitchen counter.

“It’s the same way they grow on a tree,” author Drew Henderson explains. “Let’s say I go out and chop up a hemlock, grind that into sawdust, and introduce the [reishi] spores. Within a month it will be all white with mycelium, same as any other mushroom.”

To save you the work of downing a tree, you can order a mycelium starter kit online. Indoor growing kits arrive in plastic bags filled with sterilized sawdust, called “spawn bags” or “grow blocks.” The blocks will arrive covered in mycelium’s fuzzy white growth. Some bags even arrive with mushroom bodies forming.

Set the grow block on a dinner plate or pie tin to catch excess moisture. A place that receives indirect sunlight, like a kitchen counter, is perfect. If you leave the bag sealed, it will begin to inflate as the reishis release carbon dioxide. Inside this CO2-rich environment, the reishis will form into long, thin “antlers.” If you want the reishis to have the traditional fan shape, cut slits in the plastic and roll the bag down around the growing mushroom body, which decreases the amount of carbon dioxide and lets them fan out. Mist your reishis once or twice daily with a spray bottle.

Most grow blocks produce only one crop of reishis, so for a longer-term supply order reishi spawn plugs. Select a log 2 to 4 feet long that is the right tree species for your reishi — for G. lucidum select oak, maple, or plum. Drill holes in the log in late spring or early summer and insert the spawn plugs. Your reishi logs can be kept in the garden, or, if the winter is harsh, kept inside as festive, gourmet decoration.

They don’t mind room temperature, but will do best at 70 to 80 degrees Fahrenheit. Harvest the reishis in 2 to 3 months as soon as they turn dusty-brown with spores, which Henderson warns can get “just everywhere.”

Learn how you can incorporate reishi mushrooms in this Chocolate Latte Recipe.

Lindsay Gasik likes people, plants, and places, and has no plans to call anywhere home. Check out her travel blog at Year of the Durian or catch up with her on Instagram @durianwriter.

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